i2c: tiny-usb: do not use stack as URB transfer_buffer

Patch fixes i2c-tiny-usb not to use stack as URB transfer_buffer. URB buffers
need to be DMA-able, which stack is not.

Patch is only compile tested.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c
index 05106368d405d21c1f4aae261394f25ea7b29d7b..e7d3b755af3bb3771359fcb4110310a8d6359a90 100644 (file)
--- a/drivers/i2c/busses/i2c-tiny-usb.c
+++ b/drivers/i2c/busses/i2c-tiny-usb.c
@@ -54,12 +54,16 @@ static int usb_write(struct i2c_adapter *adapter, int cmd,
 
 static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
 {
-       unsigned char status;
+       unsigned char *pstatus;
        struct i2c_msg *pmsg;
-       int i;
+       int i, ret;
 
        dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
 
+       pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);
+       if (!pstatus)
+               return -ENOMEM;
+
        for (i = 0 ; i < num ; i++) {
                int cmd = CMD_I2C_IO;
 
@@ -84,7 +88,8 @@ static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
                                     pmsg->buf, pmsg->len) != pmsg->len) {
                                dev_err(&adapter->dev,
                                        "failure reading data\n");
-                               return -EREMOTEIO;
+                               ret = -EREMOTEIO;
+                               goto out;
                        }
                } else {
                        /* write data */
@@ -93,36 +98,50 @@ static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
                                      pmsg->buf, pmsg->len) != pmsg->len) {
                                dev_err(&adapter->dev,
                                        "failure writing data\n");
-                               return -EREMOTEIO;
+                               ret = -EREMOTEIO;
+                               goto out;
                        }
                }
 
                /* read status */
-               if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) {
+               if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) {
                        dev_err(&adapter->dev, "failure reading status\n");
-                       return -EREMOTEIO;
+                       ret = -EREMOTEIO;
+                       goto out;
                }
 
-               dev_dbg(&adapter->dev, "  status = %d\n", status);
-               if (status == STATUS_ADDRESS_NAK)
-                       return -EREMOTEIO;
+               dev_dbg(&adapter->dev, "  status = %d\n", *pstatus);
+               if (*pstatus == STATUS_ADDRESS_NAK) {
+                       ret = -EREMOTEIO;
+                       goto out;
+               }
        }
 
-       return i;
+       ret = i;
+out:
+       kfree(pstatus);
+       return ret;
 }
 
 static u32 usb_func(struct i2c_adapter *adapter)
 {
-       __le32 func;
+       __le32 *pfunc;
+       u32 ret;
+
+       pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);
 
        /* get functionality from adapter */
-       if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
-           sizeof(func)) {
+       if (!pfunc || usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc,
+                              sizeof(*pfunc)) != sizeof(*pfunc)) {
                dev_err(&adapter->dev, "failure reading functionality\n");
-               return 0;
+               ret = 0;
+               goto out;
        }
 
-       return le32_to_cpu(func);
+       ret = le32_to_cpup(pfunc);
+out:
+       kfree(pfunc);
+       return ret;
 }
 
 /* This is the actual algorithm we define */